Irish scientists have discovered a new method of creating wearable sensors, by adding graphene to shop-bought rubber bands.

The scientists, part of the Advanced Materials and BioEngineering Research (Amber) centre, infused rubber bands with graphene, a “wonder material” derived from pencil lead. Graphene is 10,000 times smaller than the width of a human hair, incredibly flexible and harder than a diamond.

While rubber does not normally conduct electricity, the addition of graphene made the rubber bands electrically conductive without degrading their mechanical properties.

Tests by the team, led by Jonathan Coleman, a professor of chemical physics at TCD, showed any current flowing through the graphene-infused rubber bands was very strongly affected if the band was stretched. As a result, if the band is attached to clothing, the tiniest movements such as breath and pulse can be sensed.

Prof Coleman said the discovery opens up possibilities for the development of wearable sensors from rubber, which could be used to monitor blood pressure and respiration, or as an early warning system for cot death and sleep apnoea. The sensors could also be woven into clothing to monitor athletes’ movement or patients undergoing physical rehabilitation.

Response to motion

Prof Coleman said wearable sensors must be made of durable, flexible and stretchable materials that respond to motion.

“By implanting graphene into rubber, a flexible natural material, we are able to completely change its properties to make it electrically conductive, to develop a completely new type of sensor. Because rubber is available widely and cheaply, this unique discovery will open up major possibilities in sensor manufacturing worldwide.”

The team worked with researchers from the University of Surrey and findings have been published in ACS Nano, an international nanoscience publication.

“Until now, no such sensor has been produced that meets needs and that can be easily made. It sounds like a simple concept, but our graphene-infused rubber bands could really help to revolutionise certain aspects of healthcare,” Dr Alan Dalton from the University of Surrey said.